ASP.NET Core 6: Unhandled handling for async database operations in a service layer
I'm working through a tutorial and I'm stuck trying to I'm working with an unhandled exception when trying to perform asynchronous database operations in my ASP.NET Core 6 application..... The service layer method is supposed to fetch user details from a SQL Server database, but whenever I call it, I receive the behavior: `System.InvalidOperationException: The connection is already open.` This typically happens when I try to use a single `DbContext` instance across multiple asynchronous calls. Here’s a snippet of the service method that retrieves user information: ```csharp public async Task<User> GetUserByIdAsync(int userId) { using (var context = new ApplicationDbContext()) { return await context.Users.FindAsync(userId); } } ``` In the controller, I call this method like this: ```csharp public async Task<IActionResult> GetUser(int id) { var user = await _userService.GetUserByIdAsync(id); return user != null ? Ok(user) : NotFound(); } ``` I’ve ensured that `ApplicationDbContext` is registered in the `Startup.cs` file correctly: ```csharp services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))); ``` I've tried adding more logging around the database calls, and it seems like the scenario arises when multiple requests hit the controller simultaneously. I suspect that the `DbContext` is not properly scoped to the request. Should I be using dependency injection to manage the lifecycle of `DbContext`, or is there something else I’m missing? I'm currently using Entity Framework Core 6, and I would appreciate any insights on how to handle this situation properly. I recently upgraded to Csharp 3.9. Any advice would be much appreciated. My development environment is Linux. Is there a simpler solution I'm overlooking?